Magnetic detection coil and apparatus for magnetic field measurement

Abstract

A magnetic detection coil made of a single wire is constructed of one of superconducting and metallic materials. Four second-order differential coils are arranged so that a geometric figure obtained by connecting the respective centers of the four differential coils can form a parallelogram. By providing intersections between the four second-order differential coils, the values of magnetic flux respectively penetrating the differential coils are differentiated in three different directions.

What is claimed is: 
     
       1. A magnetic detection coil, comprising:
 a single wire of either a superconductor material or a metal material;
 wherein the single wire comprises four differential coils which are disposed such that four respective centers of the four differential coils constitute substantially four apexes of a parallelogram, and connection lines electrically connecting said four differential coils with each other and the connection lines crossing between the four differential coils, so as to measure a difference in a magnetic flux value for magnetic flux penetrating the differential coil between a pair of the differential coils, with respect to each of three different directions. 
 
 
     
     
       2. A magnetic detection coil, comprising:
 a single wire of either a superconductor material or a metal material,
 wherein the single wire comprises four differential coils which are disposed such that four respective centers of the four differential coils constitute substantially four apexes of a parallelogram, said four differential coils including a first differential coil, a second differential coil disposed adjacent to the first differential coil, a third differential coil disposed adjacent to the first differential coil and a fourth differential coil disposed adjacent to the third differential coil, first connection lines electrically connecting the first differential coil and the second differential coil with each other and the first connection lines crossing between the first differential coil and the second differential coil, so that a difference in a magnetic flux value for magnetic flux penetrating the differential coil between the first differential coil and the second differential coil is measured, second connection lines electrically connecting the third differential coil and the fourth differential coil with each other and the second connection lines crossing between the third differential coil and the fourth differential coil, so that a difference in a magnetic flux value for magnetic flux penetrating the differential coil between the third differential coil and the fourth differential coil is measured, and third connection lines electrically connecting the first differential coil and the third differential coil with each other and the third connection lines crossing between the third differential coil and the fourth differential coil, so that a difference in a magnetic flux value for magnetic flux penetrating the differential coil between the first differential coil and the third differential coil is measured. 
 
 
     
     
       3. The magnetic detection coil according to  claim 1 , wherein said parallelogram is a square. 
     
     
       4. The magnetic detection coil according to  claim 2 , wherein said parallelogram is a square. 
     
     
       5. The magnetic detection coil according to  claim 1 , wherein the respective four differential coils are first-order differential coils. 
     
     
       6. The magnetic detection coil according to  claim 2 , wherein the respective four differential coils are first-order differential coils. 
     
     
       7. The magnetic detection coil according to  claim 1 , wherein the respective four differential coils are second-order differential coils. 
     
     
       8. The magnetic detection coil according to  claim 2 , wherein the respective four differential coils are second-order differential coils. 
     
     
       9. A magnetic detection coil comprising three of the magnetic detection coils according to  claim 1 , wherein three coil disposed planes, on each of which the four differential coils of the magnetic detection coil according to  claim 1  are disposed, are disposed orthogonal to one another. 
     
     
       10. A magnetic detection coil comprising three of the magnetic detection coils according to  claim 2 , wherein three coil disposed planes, on each of which the four differential coils of the magnetic detection coil according to  claim 2  are disposed, are disposed orthogonal to one another. 
     
     
       11. A magnetic field measurement apparatus for transmitting a magnetic signal detected by a magnetic detection coil to a superconducting quantum interference device (SQUID), comprising:
 the magnetic detection coil made of a single wire of either a superconductor material or a metal material,
 wherein the single wire comprises four differential coils which are disposed such that four respective centers of the four differential coils constitute substantially four apexes of a parallelogram, and connection lines electrically connecting said four differential coils with each other and the connection lines crossing between the four differential coils, so as to measure a difference in a magnetic flux value for magnetic flux penetrating the differential coil between a pair of the differential coils, with respect to each of three different directions. 
 
 
     
     
       12. The magnetic field measurement apparatus according to  claim 11  for detecting a magnetic signal generated from a human heart. 
     
     
       13. The magnetic field measurement apparatus according to  claim 12 , wherein said human heart is of a fetus. 
     
     
       14. The magnetic field measurement apparatus according to  claim 11 , comprising means for detecting a magnetic signal generated from a human brain, and means for monitoring a neural conduction time. 
     
     
       15. The magnetic detection coil according to  claim 1 , wherein the four differential coils include a first differential coil, a second differential coil, a third differential coil and a fourth differential coil, and the difference in the magnetic flux value is ((magnetic flux penetrating the first differential coil)−(magnetic flux penetrating the second differential coil))−((magnetic flux penetrating the third differential coil)−(magnetic flux penetrating the fourth differential coil)). 
     
     
       16. The magnetic field measurement apparatus according to clam  11 , wherein the four differential coils include a first differential coil, a second differential coil, a third differential coil and a fourth differential coil, and the difference in the magnetic flux value is ((magnetic flux penetrating the first differential coil)−(magnetic flux penetrating the second differential coil))−((magnetic flux penetrating the third differential coil)−(magnetic flux penetrating the fourth differential coil)). 
     
     
       17. The magnetic detection coil according to  claim 1 , wherein said connection lines serially electrically connect said four differential coils with each other. 
     
     
       18. The magnetic detection coil according to  claim 1 , wherein said first, second, and third connection lines serially electrically connect said first differential coil with said second differential coil, said third differential coil with said fourth differential coil, and said first differential coil with said third differential coil, respectively. 
     
     
       19. The magnetic field measurement apparatus according to  claim 11 , wherein said connection lines serially electrically connect said four differential coils with each other.